Almost 60 percent of the climbers who set out to stand atop Mount McKinley succeeded this climbing season, according to the National Park Service. NPS photo.

Nearly 60 percent of the climbers who set out to stand atop Mount McKinley in Denali National Park and Preserve succeeded this climbing season. However, that accomplishment was overshadowed by the deaths of four climbers.

Among those who died on the 20,320-foot-tall mountain were two young doctors, both acclaimed climbers and physicians, who were killed June 12 when they fell down the Messner Couloir between the West Rib and the West Buttress routes. Dr. John Mislow, 39, of Newton, Massachusetts, and Dr. Andrew Swanson, age 36, of Minneapolis, Minnesota, were not unfamiliar with Mount McKinley. Indeed, in 2000 park officials presented the two men with the Denali Pro Award, an honor recognizing the highest standards in the sport for safety, self-sufficiency, and assisting fellow mountaineers.

Also dying on the mountain this season were:

* Dr. Gerald Myers, a chiropractor from Centennial, Colorado, who disappeared May 19 while making a solo bid for the summit. He was thought to have been moving light without much gear when he headed for the summit. Rangers flew dozens of hours over Mount McKinley with hopes of spotting him. Before he vanished, the 42-year-old was sighted at various elevations along the West Buttress route, the highest of which was somewhere between 18,000 and 19,000 feet. While an individual climber was observed on the summit ridge the afternoon of Wednesday, May 20, it cannot be confirmed that it was Dr. Myers.

Ironically, as rangers were searching for Dr. Myers, they discovered the bodies of two Japanese climbers who disappeared after an attempt of the Cassin Ridge in May 2008. Tatsuro Yamada and Yuto Inoue were expected to return from a climb of the Cassin Ridge on May 22, 2008. According to the journals left in their camp, the two had intended to approach their route via Kahiltna Peaks, a 5-mile-long knife-edge ridge that reaches a peak elevation of 13,440 feet. Rangers spotted the bodies of the Japanese climbers while analyzing high-resolution photographs taken of McKinley during the search for Dr. Myers.

* William Hearne was the first climber to die on the mountain this climbing season, though his death was attributed to a heart attack, not a climbing accident. Mr. Hearne, of Fairport, New York, was on a six-member team being led by Mountain Trip guides. They began their ascent of McKinley on May 1. Mr. Hearne collapsed shortly before 4:00 p.m. after his team had hauled gear from their camp at 11,200 feet to a cache site at 13,500 feet, just above the location known as Windy Corner.

The Mount McKinley climbing season typically extends from April through early July. May is the peak month for climbing, since that is when the weather tends to be least miserable. Indeed, some believe summiting McKinley is one of the toughest tasks because of the weather that sweeps up from the Gulf of Alaska. It is the terrible weather -- severe cold, very high winds, blinding snows -- in combination with glacier travel that makes McKinley notoriously dangerous. Mount McKinley climbs on average take about 18 days. Some of the time is used to pause at progressively higher elevations for acclimation to lower oxygen levels. The mountain's weather being as lousy as it is, climbers also tend to spend a lot of time holed up in their tents and waiting out storms. About 75 percent of the climbers use the classic West Buttress approach to the summit, but there are other, even more difficult routes, such as the West Rib and Cassin Ridge.

As for this summer's climbing season, 1,171 climbers registered to assault Mount McKinley, and 620, or 57 percent, summited. As of July 8, though, there were still 69 climbers on the mountain, so the number of those who reached the summit could change. Just 15 climbers registered to take on Mount Foraker, and eight reached the summit of the 17,400-foot peak.